Step inside a giant Buddha
Many of Japan's giant Buddhas and statues of Kannon, the Buddhist goddess of mercy, are hollow, and at these you can walk inside. Enter through a door in the back or at the feet, then climb past Buddhist images and exhibits; in the tallest ones, windows near the top look out over the landscape. All of them are day trips from Tokyo.
Kamakura's Great Buddha is a 13th-century bronze statue that has sat in the open air for about 500 years, since storms and a tsunami destroyed the hall around it. For 50 yen more, you can step inside its hollow body and see the seams where the bronze sections were cast together. The visit takes only a few minutes, so it fits easily into a day in Kamakura.
At 120 meters including its base, this bronze Buddha in Ibaraki is one of the tallest statues in the world. An elevator inside takes you up to windows 85 meters above the ground, and the floors below hold exhibits, including a corner where you can copy a sutra by hand. Take a bus from JR Ushiku Station, and plan on half a day with the gardens.
This 42-meter Kannon stands on a hill above Takasaki and is hollow up to her shoulders. Climb narrow stairs through nine floors, each with its own Buddhist statues and figures of revered monks, to look out over the city. Takasaki is about an hour from Tokyo by shinkansen.
Inside this 56-meter Kannon on the Chiba coast, a spiral staircase of about 300 steps winds up through 20 floors. Small windows in her arms, shoulders, and crown look out over Tokyo Bay. It's about a 30-minute walk from Sanukimachi Station, and the statue may close in bad weather or snow.
This giant white bust of Kannon looks out over Ofuna Station from the hill beside it. Enter through her back to see a thousand small Buddha figures and the model the statue was made from. Ofuna is on the train line from Tokyo to Kamakura, so it's easy to stop on the way.